1. Field of the Invention
The present invention relates to a disk device, or more in particular to a disk device which has a high sound-insulation capability for preventing noise generated in the disk device from leaking out and which comprises a ventilation structure for permitting air to flow between the inside and outside of the device in whatever environment the device is used in a computer system.
2. Description of the Related Art
In recent years, disk devices such as a magnetic disk device and an optical disk device have come to be used as storage devices for the computer. These devices are used with the computer in various environments, and therefore, require adjustment of the pressure difference between the inside and outside of the device caused by the change in the ambient temperature or pressure. For this purpose, ventilation holes (also called breathing holes) are usually formed in the cover of the disk device.
In the case where a disk device out of operation is allowed to stand in an ordinary environment, such substances as S or SO.sub.2 (as the result of diffusion of the molecules thereof) are liable to intrude into the device by way of the ventilation between the inside and outside of the disk device. Also, dust and corrosive gases which may intrude into the device have a harmful effect on the internal members such as the disks of the disk device.
In view of this, a ventilation structure (also called a breathing structure) has conventionally been proposed to prevent intrusion of harmful gases into the disk device by a gas adsorption filter mounted in the ventilation holes of the disk device.
However, in the conventional disk device, a filter is usually attached to the interior of the cover. In this case, a storage space for the filter must be formed in the reverse side of the cover to avoid contact with the disk or a metal cover is required on the filter to suppress the expansion of the filter. Further, the ventilation holes of the conventional disk device, which are formed in the upper surface of the cover, are often closed and fail to function depending on the structure of the mounting frame of the disk device built in the system.
Furthermore, the noise generated in the device sometimes leaks out in view of the fact that the disks are rotating at high speed and the head accessing the disks is swung and controlled by an actuator in the device in operation.